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FreeBSD-SA-13:04.bind                                       Security Advisory
                                                          The FreeBSD Project

Topic:          BIND remote denial of service

Category:       contrib
Module:         bind
Announced:      2013-04-02
Credits:        Matthew Horsfall of Dyn, Inc.
Affects:        FreeBSD 8.4-BETA1 and FreeBSD 9.x
Corrected:      2013-03-28 05:35:46 UTC (stable/8, 8.4-BETA1)
                2013-03-28 05:39:45 UTC (stable/9, 9.1-STABLE)
                2013-04-02 17:34:42 UTC (releng/9.0, 9.0-RELEASE-p7)
                2013-04-02 17:34:42 UTC (releng/9.1, 9.1-RELEASE-p2)
CVE Name:       CVE-2013-2266

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/>.

I.   Background

BIND 9 is an implementation of the Domain Name System (DNS) protocols.
The named(8) daemon is an Internet Domain Name Server.  The libdns
library is a library of DNS protocol support functions.

II.  Problem Description

A flaw in a library used by BIND allows an attacker to deliberately
cause excessive memory consumption by the named(8) process.  This
affects both recursive and authoritative servers.

III. Impact

A remote attacker can cause the named(8) daemon to consume all available
memory and crash, resulting in a denial of service.  Applications linked
with the libdns library, for instance dig(1), may also be affected.

IV.  Workaround

No workaround is available, but systems not running named(8) service
and not using base system DNS utilities are not affected.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.

2) To update your vulnerable system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch http://security.FreeBSD.org/patches/SA-13:04/bind.patch
# fetch http://security.FreeBSD.org/patches/SA-13:04/bind.patch.asc
# gpg --verify bind.patch.asc

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

Recompile the operating system using buildworld and installworld as
described in <URL:http://www.FreeBSD.org/handbook/makeworld.html>.

Restart the named daemon, or reboot the system.

3) To update your vulnerable system via a binary patch:

Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in FreeBSD.

Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/8/                                                         r248807
stable/9/                                                         r248808
releng/9.0/                                                       r249029
releng/9.1/                                                       r249029
- -------------------------------------------------------------------------

VII. References

https://kb.isc.org/article/AA-00871

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-2266

The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-13:04.bind.asc
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